1. Field of the Invention
This invention relates to an automatic programming method and device for multi-system machine tools. Particularly, it relates to a programming method and device for automatically deciding a machining system to handle a particular machining step, deciding a machining order in the machining step or deciding a waiting order between an interfering machining systems, on the basis of machining informations including a machining step information, thereby generating a machining program based on such informations. The method and device is applicable to NC machine tool, Electric Discharge Machine and the like.
2. Description of Related Art
FIG. 67 exemplifies an automatic programming device for multi-system machine tools in the related art. An operator inputs machining informations such as a machining step information and the like into an automatic programming information control unit 1 through an input unit 3 and an input control unit 4. A machining program control unit 2 generates a machining program on the basis of the machining informations. Thus generated machining program is stored in a memory 8 such as a semiconductor memory device or a hard disk via a memory control unit 7. The operator carries out such successive operations interactively while seeing a screen of a display 6 such as CRT which is connected to a display control unit 5.
A multi-system machining program is generated as follows in the automatic programming device in the related art.
First, the operator inputs a work information, tool informations for respective systems, a machining step information, etc. Then, the operator inputs them through the input unit 3 while checking the input informations via the display 6. The work information, tool informations, machining step information and the like are input thereafter in the automatic programming information control unit 1 from the input control unit 4.
However, a machining program for each system cannot be generated only with the above processes. This is because there remain several matters to be decided. Namely, it should be further determined which machining system is available for each machining step, which machining system should be used for the machining, in which order a plurality of machining steps should be performed in the same system.
Therefore, the operator has to determine first of all which system can handle a desired machining step wherein a particular workpiece and tool are defined in the workpiece information and tool information for each system or the like. For example, in case of drilling, the machining system must have at least one drilling tool, and the tool must have the same diameter as a diameter of a hole to be drilled. If none of the systems is suitable for the machining, the operator must change or add workpieces or tools. Namely, the operator has to consider a variety of things mentioned above.
If a plurality of systems are suitable for machining, the operator must decide only one system for actually performing the machining. For example, he or she determines that, if the first system and the second system are available for a particular machining step, such a machining step should be always treated by the first system. After the operator finishes deciding machining systems which should handle respective machining steps, he or she is required to determine an order of the machining steps in each of the systems. For example, the operator determines that a drilling step should be done always after a grooving step. When the operator decides all the above matters, preparation for generating a machining program for each system is completed.
Then, the automatic programming information control unit 1 outputs the given machining step information, workpiece information and tool information to the machining program control unit 2. The automatic programming information control unit 1 also outputs the information showing which system be assigned to which machining step and the machining order information in each system, both of which are determined by the operator. The machining program control unit 2 generates machining programs for the machining systems, respectively, on the basis of the above informations. The machining programs for the respective systems are stored in the memory 8 through the memory control unit 7.
However, with the automatic programming device of the related art, the operator has to decide and input the above mentioned various matters in advance: which system is available for which machining step, which system should perform that specific machining step if there are plural systems available, in what order the machining steps should be treated in that machining system, etc. Accordingly, it is impossible to make up the machining program for each system until the input work of the above matters is finished.
In addition, another work is required after the operator has decided the machining order in the system and starts machining with plural machining systems at the same time. Namely, he or she must check whether or not it is possible to perform a machining step in one system simultaneously with a machining step in another system. If it is impossible, the operator has to decide a waiting order between the interfering systems, i.e. which system should wait which system. If the program for multi-system machine tool is carried out without such waiting operation, tools may collide with each other. Otherwise, machining becomes impossible with respect to the machining steps which can be performed provided that machinings in the other machining system are completed.
For example, in case of machining the same workpiece in one and the other machining steps which belong to different systems, it is necessary to carry out a step for rough machining before the other machining step. If the other machining step is performed before the rough machining, cutting may be so large that a tool is possibly damaged. In this case, any steps other than the rough machining step should wait completion of that rough machining step. Thus, there arises a necessity for waiting in machining steps which belong to different systems.
Moreover, it is impossible to carry out a machining step in which the workpiece is machined while being rotated at the same time with a machining step in which the workpiece is machined without rotation. Accordingly, unless the machining step to be treated first in one system is completed, the machining step treated in the other system cannot be started. Thus, there is another necessity for waiting in machining steps which belong to different systems.
Furthermore, if there is a possibility that tools interfere with each other in case of performing plural machining steps, unless the machining step to be treated first in one system is completed, the machining step treated in the other system should not be started to prevent collision of the tools. Thus, there is further necessity for waiting in machining steps which belong to different systems. As mentioned above, the operator must consider various conditions for waiting between machining steps handled by different systems in order to designate a machining order therein. Namely, in the automatic programming device for multi-system machine tool of the related art, the operator has to judge and input beforehand all troublesome works by himself or herself, such as a machining order in a machining system, a waiting order between different machining systems and the like.
As mentioned above, the operator needs to do many works for preparation of generating the machining programs for the systems. Therefore, the machining program preparing work depends much upon operator's skill. If the decisions are wrong or improper in such preparatory works, several problems arise. For example, the tool undergoes excessive load and damaged in a short time, machining accuracy of the workpiece is lowered, or the machining becomes impossible at worst. Therefore, the operator is required to be highly skilled. As a result, efficiency for generating the machining programs is very low.
On the other hand, Japanese Patent Publication (Kokai) No. 4-360749 discloses a device in which an operator inputs data of all machining shapes of through holes machined in a combined machining. Then, the device automatically divides the machining shape data into the first machining data and the second machining data to generate a program. However, with such an automatic machining step deciding method, the operator must judge and input several things when performing various machining with the multi-system tool machine, as in the above mentioned related art. Namely, he or she has to determine beforehand which system is available for which machining step, which system should perform that machining step if there are plural systems available, in what order the machining steps should be treated in the system, etc.